The present invention is related to an implement mounting arrangement on a vehicle, and more particularly to a base frame assembly which is universally secured to the vehicle and an implement support assembly hingedly mounted on the base frame assembly. Appropriate actuators are secured therebetween to adjust the orientation of the implement support assembly relative to the travel direction of the vehicle.
Heretofore, motor graders have utilized a pull-type drawbar which is universally mounted at its front end to the motor grader frame and is suspended at its rear end by hydraulic jacks. A rotatable support circle is secured to the drawbar and a grader blade is mounted on and below the circle, all in a conventional manner. Advantageously, the rear end of the drawbar is side shiftable to extend the side reaching capability of the blade. Exemplifying the prior art in this area are the following two U.S. Patents, both of which are assigned to the assignee of the present invention, U.S. Pat. Nos.:
3,677,350 issued July 18, 1972 to H. M. Johnson et al PA1 3,739,861 issued June 19, 1973 to H. M. Johnson et al.
While such blade mounting arrangements have proven extremely effective and have met with universal acceptance, customer demand for higher horsepower vehicles and larger load capacity earthmoving blades continues to grow. However, the usual circle for rotatably supporting the blade must be increased in diameter to resist the greatly increased forces which would thereby be encountered. This would result in a marked rise in cost and a decreased operator visibility of the blade. Furthermore, an excessive amount of longitudinal space would be required in order to mount and maneuver the heavier circle arrangement between the front and rear wheels of the vehicle. Since the wheel base of these motor graders is already significantly extended in order to provide the superior dimensional control and fine finishing capabilities of the blade, any significant increase thereof is detrimental to maneuverability of the motor grader.
Moreover, another significant problem is that blade loads are conventionally transferred into the front part of the main frame. Thus, the heavier forces which would be encountered would require that the longitudinally oriented main frame would have to be significantly strengthened from the front portion back to the rear portion thereof, which rear portion is inherently heavier in its construction because it supports the power plant and the driving wheels.